Why is it so difficult to determine the sequence of hominin ancestors that have led to modern homo sapiens?

Efficiency is the percent of work put into a machine by the user (input work) that becomes work done by the machine (output work)

Wht happens as electrons in the electron transport chain release their energy

Microorganisms aren’t all decomposers; in fact, many act as producers or primary consumers in an ecosystem. how do microorganisms that act as producers benefit the rest of an ecosystem in terms of energy transfer? what about microorganisms that act as primary consumers?